Development device and image forming apparatus incorporating same

Abstract

A development device includes a development portion, to develop a latent image formed on a latent image carrier with developer, disposed close to the latent image carrier; a developer agitation container to agitate the developer, provided separately from the development portion; a transport system connecting the development portion and the developer agitation container, through which the developer is transported from the developer agitation container to the development portion by air; and a developer retainer to temporarily retain the developer, disposed downstream from the transport system, to which the developer remaining in the transport system escapes.

What is claimed is: 
     
       1. A development device comprising:
 a development portion, to develop a latent image formed on a latent image carrier with a developer, disposed close to the latent image carrier; 
 a developer agitation container to agitate the developer, provided separately from the development portion; 
 a transport system connecting the development portion and the developer agitation container, through which the developer is transported from the developer agitation container to the development portion by air; and 
 a developer retainer to temporarily retain the developer, disposed downstream from the transport system, to which the developer remaining in the transport system escapes, 
 wherein, after the developing operation, a control is carried out to move the developer remaining in the transport system to the developer retainer disposed downstream from the transport system. 
 
     
     
       2. The development device according to  claim 1 , wherein the transport system comprises a vertical tube through which the developer is transported upward by the air in a substantially vertical direction, and the developer remaining in the vertical tube is moved to the developer retainer disposed downstream from the transport system. 
     
     
       3. The development device according to  claim 2 , wherein the developer retainer is configured to prevent the developer from flowing back down the vertical tube of the transport system. 
     
     
       4. The development device according to  claim 3 , wherein the transport system further comprises a horizontal tube through which the developer is transported by the air in a substantially horizontal direction, and the horizontal tube is disposed downstream from the vertical tube so that the developer is prevented from flowing in reverse from the developer retainer to the vertical tube. 
     
     
       5. The development device according to  claim 1 , further comprising:
 a developer feeder to feed the developer from the developer agitation container to the transport system; 
 a pneumatic device to generate air that moves the developer from the developer feeder to the development portion through the transport system; 
 a developer circulation member provided inside the developer portion, to circulate the developer in the development portion conveyed from the developer agitation container; and 
 a collection system connecting the development portion and the developer agitation container, through which the developer after circulation in the development portion is transported to the developer agitation container, 
 wherein, in a state in which the development device receives a command to stop, the developer feeder is stopped, the developer in the transport system escapes to the developer retainer, and then the pneumatic device is stopped. 
 
     
     
       6. The development device according to  claim 5 , further comprising:
 a control panel to transmit commands to activate and stop components in the development device; 
 multiple sensors to check operation of the components in the development device; and 
 a controller having an input side connected to the sensors and an output side connected to at least the developer feeder and the pneumatic device, 
 wherein, when the command to stop the operation of the development device is transmitted from the control panel, the controller stops the pneumatic device after the controller stops the developer feeder and the developer in the transport system escapes to the developer retainer. 
 
     
     
       7. The development device according to  claim 6 , wherein the developer in the transport system escapes to the developer retainer when the development device is first activated. 
     
     
       8. The development device according to  claim 1 , further comprising:
 a developer feeder to feed the developer from the developer agitation container to the transport system; 
 a pneumatic device to generate air that moves the developer from the developer feeder to the development portion through the transport system; 
 a developer circulation member provided inside the developer portion, to circulate the developer in the development portion conveyed from the developer agitation container; and 
 a collection system connecting the development portion and the developer agitation container, through which the developer after circulation in the development portion is transported to the developer agitation container, 
 wherein, in a state in which the development device receives a command to start operation, the developer feeder is activated, the developer in the transport system escapes to the developer retainer, and then the pneumatic device is activated. 
 
     
     
       9. The development device according to  claim 4 , further comprising:
 a control panel to transmit commands to activate and stop components in the development device; 
 multiple sensors to check operation of the components in the development device; and 
 a controller having an input side connected to the sensors and an output side connected to at least the developer feeder and the pneumatic device, 
 wherein, when the command to start the operation of the development device is transmitted from the control panel while the development device is stopped, the controller activates the pneumatic device, after the controller activates the developer feeder and the developer in the transport system escapes to the developer retainer. 
 
     
     
       10. An image forming apparatus comprising:
 a latent image carrier to carry a latent image; and 
 a development device comprising: 
 a development portion, to develop a latent image formed on a latent image carrier with developer, disposed close to the latent image carrier; 
 a developer agitation container to agitate the developer, provided separately from the development portion; 
 a transport system connecting the development portion and the developer agitation container, through which the developer is transported from the developer agitation container to the development portion by air; and 
 a developer retainer to temporarily retain the developer, disposed downstream from the transport system, to which the developer remaining in the transport system escapes, 
 wherein, after the developing operation, a control is carried out to move the developer remaining in the transport system to the developer retainer disposed downstream from the transport system. 
 
     
     
       11. The image forming apparatus according to  claim 10 , further comprising:
 a control panel to transmit commands to activate and stop components in the development device; 
 multiple sensors to check operation of the devices in the image forming apparatus; and 
 a controller having an input side connected to the sensors and an output side, 
 wherein the development device further comprises:
 a developer feeder to feed the developer from the developer agitation container to the transport system, connected to the output side of the controller; 
 a pneumatic device to generate air to move the developer from the developer feeder to the development portion through the transport system, connected to the output side of the controller; 
 a developer circulation member provided inside the developer portion, to circulate the developer in the development portion conveyed from the developer agitation container; and 
 a collection system connecting the development portion and the developer agitation container, through which the developer after circulation in the development portion is transported to the developer agitation container, 
 
 wherein, when the command to stop operation of the development device is transmitted from the control panel, the controller stops the pneumatic device, after the controller stops the developer feeder and the developer in the transport system escapes to the developer retainer. 
 
     
     
       12. The image forming apparatus according to  claim 11  wherein the developer in the transport system escapes to the developer retainer when the development device is first activated. 
     
     
       13. The image forming apparatus according to  claim 11  wherein the developer in the transport system escapes to the developer retainer in a time interval during which no printing operation is being performed by the image forming apparatus, as determined by job data stored in the image forming apparatus. 
     
     
       14. The image forming apparatus according to  claim 10 , further comprising:
 a control panel to send commands to activate and stop components in the development device; 
 multiple sensors to check operation of the devices in the image forming apparatus; and 
 a controller having an input side connected to the sensors and an output side, 
 wherein the development device further comprises:
 a developer feeder to feed the developer from the developer agitation container to the transport system, connected to the output side of the controller; 
 a pneumatic device to generate air to move the developer from the developer feeder to the development portion, connected to the output side of the controller; 
 a developer circulation device provided inside the developer portion, to circulate the developer conveyed from the developer agitation container to the development portion; and 
 a collection system connecting the development portion and the developer agitation container, through which the developer after circulation in the development portion is transported to the developer agitation container, 
 
 wherein when the command to start operation of the development device is transmitted from the control panel, the controller activates the pneumatic device, after the controller activates the developer feeder and the developer in the transport system escapes to the developer retainer.